Women with sleep disturbances may find their condition worsens with menopause, and approximately 28% to 63% of postmenopausal women report that they have insomnia. While aging itself may be a factor, other possible causes, related specifically to menopause, could be at play as well. For example, night sweats (the nighttime version of hot flashes) often disturb sleep and contribute to insomnia. But the effects of conventional hormone therapy on sleep quality have produced mixed results. And, because of the known side effects of hormone therapy, many women have sought more natural alternatives to hormones for relief from menopause symptoms.
Isoflavones from soybeans have been extensively studied for their ability to alleviate hot flashes. The results overall from these studies indicate isoflavones reduce the frequency and severity of hot flashes by approximately 50 percent. But the first study to examine the effects of isoflavones on insomnia in postmenopausal women was just published.
Researchers from the Federal University in São Paolo, Brasil, gave 80 milligrams of isoflavones for four months to postmenopausal women who suffered from insomnia. Women in a control group received a placebo.
Eighty milligrams of isoflavones is the amount found in about three servings of traditional soyfoods. One serving is a cup of soymilk or half cup of tofu. The effect on sleep was determined subjectively by the use of questionnaires and objectively, by the use of a polysomnography, which is a comprehensive recording of the biophysiological changes that occur during sleep.
Among the thirty-eight women in the study, polysomnography revealed a significant increase in sleep efficiency in the isoflavone group when compared with the placebo group. Also, isoflavones caused a decrease in the intensity and number of hot flashes and the frequency of insomnia. At the end of the study, 63.2 percent of the women in the control group had moderate or intense insomnia compared to 36.9 percent of the women who consumed the isoflavones. The improvement in hot flashes was unrelated to the improvement in insomnia. The results of this study should provide hope for the millions of women suffering from insomnia although because of its small size, confirmation of the results in follow up research is needed before definite conclusions can be made.
Hachul H, Brandao LC, D’Almeida V, Bittencourt LR, Baracat EC, Tufik S. Isoflavones decrease insomnia in postmenopause. Menopause 2010.